Cinacalcet treatment and serum FGF23 levels in haemodialysis patients with secondary hyperparathyroidism.

BACKGROUND: Elevated fibroblast growth factor 23 (FGF23) is associated with adverse clinical outcomes and development of secondary hyperparathyroidism (SHPT) refractory to active vitamin D. Cinacalcet hydrochloride is effective in treating SHPT, but little is known as to whether treatment with cinacalcet alters these levels and whether pretreatment FGF23 levels predict response to this therapy. METHODS: We measured serum full-length FGF23 levels in 55 haemodialysis patients, who participated and completed the 52-week, multicentre, open-label single-arm trial that examined the effectiveness of cinacalcet for treating SHPT. In the study, alteration of vitamin D dosage was not permitted except for the case in which serum calcium could not be managed by calcium carbonate adjustment alone. RESULTS: After 12 weeks of cinacalcet treatment, FGF23 levels decreased significantly concomitantly with a significant reduction in intact parathyroid hormone (PTH) levels. These responses were sustained >52 weeks. In multivariate regression analyses, changes from baseline in serum FGF23 were associated with changes in serum calcium and phosphorus but not with intact PTH at each time point of measurements (Week-12, Week-24 and Week-52). Baseline FGF23 was not associated with the likelihood of achieving an intact PTH <180 pg/mL at the study end. CONCLUSIONS: Cinacalcet lowers serum FGF23 in haemodialysis patients with SHPT independently of the effects of active vitamin D. Pretreatment FGF23 cannot predict treatment response to cinacalcet in this setting. The precise mechanism of FGF23 reduction by cinacalcet and its clinical impact on outcomes in patients remain to be investigated.

Transarterial renal embolization for enlarged horseshoe kidney.

A 56-year-old Japanese man was admitted to our hospital with abdominal fullness in June 2006. He had been diagnosed as having a horseshoe kidney by computed tomography in January 2002. At that time, renal dysfunction (serum creatine: 2.0 mg/dl) was detected. Even after hemodialysis was started for end-stage renal failure in March 2006, his abdominal fullness became progressively worse. CT scanning showed a markedly enlarged horseshoe kidney. Transarterial embolization (TAE) was performed via the right renal arteries with 14 platinum microcoils; the left renal arteries were not embolized in order to preserve sufficient parenchyma and a urine volume of more than 1,000 ml daily. Two years after TAE, a decrease in the size of the left kidney was noted along with the right kidney. However, urine output was still more than 1,000 ml daily. It is possible that one kidney compressed the contralateral kidney, resulting in enlargement of both components of the horseshoe kidney and renal dysfunction. TAE may be a useful option for obstructive uropathy in patients with horseshoe kidney, which has conventionally been treated surgically.

A case of primary hyperparathyroidism with severe bone and renal changes.

We report a 79-year-old Japanese woman who had primary hyperparathyroidism (HPT) with end-stage renal disease and severe bone changes. In 2004, she began to experience pain in her shoulders and knees, as well as muscle weakness and anorexia. She already had renal failure with a serum Cr of 4.7 mg/dl, while serum calcium was 9.6 mg/dl, PTH was 2,710 pg/ml, and serum alkaline phosphatase was 923 mU/ml. Multiple fractures of the pelvic bones and lumbar spine, osteoporosis, and subperiosteal bone resorption were detected. Although hemodialysis (HD) was started in February 2005, her symptoms became more severe. Total parathyroidectomy (PTX) and right iliac crest bone biopsy were performed. Histomorphometric analysis of the cancellous bone indicated a diagnosis of osteitis fibrosa, but a reduction of cortical bone and near absence of cancellous bone were also apparent. This showed that bone resorption by osteoclasts was predominant over bone formation by osteoblasts. Soon after PTX, her pain subsided completely. We conclude that primary HPT should be detected and treated early enough to avoid renal damage, since renal dysfunction markedly accelerates bone changes in patients with primary HPT.

Infected hepatic and renal cysts: differential impact on outcome in autosomal dominant polycystic kidney disease.

BACKGROUND: Infected cysts are a frequent and serious complication of autosomal dominant polycystic kidney disease. Such infections are classified into those affecting hepatic cysts and those affecting renal cysts. The purpose of this study was to compare the clinical course of infected hepatic cysts with that of infected renal cysts in patients with autosomal dominant polycystic kidney disease. METHODS: We analyzed 43 patients referred to us for additional treatment of severely infected cysts between January 2004 and December 2006. All patients who required further treatment in addition to antibiotic therapy were included. RESULTS: Aspiration was performed in all 28 patients with infected hepatic cysts. As a result, 17 patients were cured, 4 remain under treatment, and 6 died. One patient was cured by partial hepatectomy. Among the 15 patients with renal cysts, aspiration was performed in 4 with identifiable infected cysts, while renal transcatheter arterial embolization after appropriate antibiotic therapy was performed in 11 without identifiable infected cysts. No patient developed recurrence. CONCLUSION: In patients with infected renal cysts, aspiration or renal transcatheter arterial embolization after appropriate antibiotic therapy was effective. Although aspiration was often effective in patients with infected hepatic cysts, a good outcome was less likely than in those with renal cysts.

Plasma adiponectin: a predictor of coronary heart disease in hemodialysis patients--a Japanese prospective eight-year study.

BACKGROUND/AIM: Plasma adiponectin may play a protective role in the pathogenesis of cardiovascular disease in hemodialysis (HD) patients. We examined the effect of plasma adiponectin levels on the prognosis of the HD patients. METHODS: 68 HD patients (male:female = 38:30) were subjected to plasma adiponectin measurement in 1998 and followed up over 8 years. RESULTS: Plasma adiponectin concentrations differed between male and female patients (9.3 vs. 15.7 microg/ml). The plasma adiponectin concentration as a whole was positively correlated with serum high-density lipoprotein cholesterol and negatively with serum creatinine and waist circumference. During an 8-year follow-up, the cardiac events occurred in 7 of 38 men and in 10 of 30 women. Cox's proportional hazard model analysis in a stepwise manner revealed that coronary heart disease (CHD) was associated with intact parathyroid hormone concentration, age, and the presence of diabetes in men whereas plasma adiponectin concentration was the most powerful single predictor in women. The impact of the plasma adiponectin concentration was strengthened by Kaplan-Meier survival analysis. In the group with a lower plasma adiponectin concentration, CHD events were significantly increased in men (p = 0.043) and in women (p = 0.007). CONCLUSION: Plasma adiponectin concentration may predict CHD outcomes in HD patients.

Successful treatment of primary AL amyloidosis by VAD therapy, high-dose melphalan, and autologous peripheral stem cell transplantation.

We report a 58-year-old Japanese man with primary systemic AL amyloidosis who achieved disappearance of proteinuria including Bence-Jones protein (lambda-type) after two courses of VAD therapy (vincristine, doxorubicin, and dexamethasone) and subsequent high-dose melphalan, followed by autologous peripheral blood stem cell transplantation. Because this patient did not have any apparent amyloidosis-related heart or liver damage and met all of the eligibility criteria for this therapy, this treatment was performed. Both proteinuria and M-protein disappeared completely, and he is doing well clinically at 19 months after treatment. However, amyloid deposits were still found in the kidneys, including the glomeruli and tubulointerstitium, when renal biopsy was done at 8 months after treatment. In the future, we may reach a time when clinical remission corresponds to histological remission.

[Basic and clinical aspects of calcimimetics. Cinacalcet, effect and mechanisms of action].

Calcimimetics drug such as cinacalcet suppress the secretion of parathyroid hormone by sensitizing parathyroid calcium receptors to extracellular ionized calcium. Standard treatment for secondary hyperparathyroidism is associated with the risk of hypercalcemia, but cinacalcet don't induce elevation of serum calcium. And it is reported that cinacalcet attenuates parathyroid hyperplasia and it effects on other organs.

Percutaneous transcatheter hepatic artery embolization for liver cysts in autosomal dominant polycystic kidney disease.

BACKGROUND: We have achieved renal contraction therapy in patients with autosomal dominant polycystic kidney disease (ADPKD) by means of renal transcatheter arterial embolization (TAE) using intravascular coils, decreasing renal size and improving quality of life in almost all patients. We presently perform hepatic TAE in patients with intractable symptomatic polycystic liver. STUDY DESIGN: Uncontrolled trial. SETTING & PARTICIPANTS: 30 patients with ADPKD referred for arteriography to an academic medical center. 22 patients had kidney failure treated by means of dialysis. INTERVENTION: We embolized arteries supplying hepatic segments replaced by cysts that were associated with well-developed hepatic arteries, but obstructed intrahepatic portal veins. OUTCOMES & MEASUREMENTS: Various volumes before and after TAE were compared by using computed tomography and National Institutes of Health Image software in 30 patients with follow-up computed tomography 18 to 37 months after therapy. RESULTS: Total liver volume and total intrahepatic cyst volume decreased from 7,882 +/- 2,916 and 6,677 +/- 2,978 to 6,041 +/- 2,282 and 4,625 +/- 2,299 cm(3), respectively (P < 0.0001 for both). Fractions of remaining (FR) total liver volume and FR of intrahepatic cyst volume were 78.8% +/- 17.6% and 70.4% +/- 20.9%, respectively. Hepatic parenchyma increased from 1,205 +/- 250 to 1,406 +/- 277 cm(3) (P = 0.0004). In 29 of 30 patients, both total liver volume and intrahepatic cyst volume decreased; in 1 patient, total liver volume increased from 5,755 to 7,069 cm(3), whereas cysts enlarged from 4,500 to 5,531 cm(3). No serious complications were experienced. In 24 patients, the post-TAE course was favorable. TAE failed to benefit 6 patients because of unrelated hepatic infection, peritonitis, hepatic failure, acute leukemia, or pelvic fracture. LIMITATIONS: Absence of a control group. CONCLUSIONS: TAE may be an option for patients with ADPKD with symptomatic polycystic liver who are not candidates for surgical treatment.

Induction of anti-carbonic-anhydrase-II antibody causes renal tubular acidosis in a mouse model of Sjogren's syndrome.

BACKGROUND/AIM: We recently reported that renal tubular acidosis (RTA) in Sjogren's syndrome (SjS) is associated with high titers of an autoantibody against carbonic anhydrase (CA) II, an important enzyme in renal acid-base regulation. The purpose of this study was to determine whether a CA-II antibody could cause RTA in a mouse model of SjS. METHODS: PL/J mice were immunized with human CA II to induce CA II antibody formation, whereas controls were injected with phosphate-buffered saline and adjuvant. After 6 weeks, anti-CA-II antibody titers were measured, then ammonium chloride was administered orally for 1 week to detect any acidification defect. RESULTS: CA-II-immunized mice showed higher anti-CA-II antibody titers than control mice. Pathologically, lymphocytic and plasma cell infiltration was seen in the salivary glands and kidneys of CA-II-immunized mice, but not in controls. On acid loading, blood pH and urine pH decreased in both groups of mice, but the slope of urine pH versus blood pH was less steep in the CA-II-immunized mice, suggesting that these mice had an impaired ability to reduce their urine pH in the face of metabolic acidosis. CONCLUSION: CA-II-immunized mice had a urinary acidification defect, which may be similar to that seen in patients with SjS.

[Therapeutic agents for disorders of bone and calcium metabolism. The calcimimetic cinacalcet HCl].

Calcimimetics drug such as cinacalcet suppress the secretion of parathyroid hormone by sensitizing parathyroid calcium receptors to extracellular ionized calcium. Standard treatment for secondary hyperparathyroidism is associated with the risk of hypercalcemia, but cinacalcet don't induce elevation of serum calcium. And some studies were reported the use of cinacalcet not only to manage primary hyperparathyroidism, but also secondary hyperparathyroidism in nondialyzed stage, renal transplant patients and parathyroid carcinoma.

Intravenous calcitriol therapy increases serum concentrations of fibroblast growth factor-23 in dialysis patients with secondary hyperparathyroidism.

BACKGROUND/AIMS: Fibroblast growth factor-23 (FGF-23) is a recently discovered phosphaturic factor. Although increased levels of serum FGF-23 have been reported in dialysis patients, the role of high FGF-23 levels remains unclear. Since FGF-23 is associated also with vitamin D metabolism, we examined the changes of serum FGF-23 levels in chronic dialysis patients treated with intravenous calcitriol therapy. METHODS: Thirty patients with severe secondary hyperparathyroidism were treated with intravenous calcitriol (0.5-1.0 microg) two or three times per week for 6 months. The changes of serum levels of calcium, phosphate, intact PTH, and FGF-23 were evaluated. RESULTS: Baseline serum FGF-23 levels were markedly high. By intravenous calcitriol therapy, intact PTH levels decreased effectively in the first month (p < 0.001). In contrast, FGF-23 levels increased gradually during the study period (p = 0.027). The Delta serum FGF-23 level was significantly correlated with the total doses of calcitriol injected intravenously in 6 months in patients with refractory secondary hyperparathyroidism (R2 = 0.147; p = 0.036). CONCLUSIONS: Intravenous calcitriol decreased serum intact PTH level and increased serum FGF-23 levels significantly. Extremely high levels of serum FGF-23 in these patients may be attributed, at least in part, to the cumulative dose of vitamin D.

[Functional disorder of the parathyroid gland and vascular calcification in hemodialysis patients].

In uremia, hyperparathyroidism induces hypercalcemia and hyperphosphatemia. Relative hypoparathyroidism also causes hypercalcemia and hyperphosphatemia due to the low buffering capacity of the bone. Thus control of PTH within target range is very important.

Total parathyroidectomy reduces elevated circulating fibroblast growth factor 23 in advanced secondary hyperparathyroidism.

BACKGROUND: Secondary hyperparathyroidism is a common complication in patients with stage 5 chronic kidney disease (CKD), accelerated by hyperphosphatemia. Fibroblast growth factor 23 (FGF-23), a phosphorus-regulating protein, has key roles in several phosphate-wasting disorders. The aim of this study is to examine the association of advanced secondary hyperparathyroidism with circulating FGF-23 levels. METHODS: Fifteen patients with marked secondary hyperparathyroidism (parathyroid hormone [PTH], 990 +/- 118 pg/mL [ng/L]) were enrolled. All underwent parathyroidectomy with forearm autotransplantation (PTX), and their FGF-23 levels were measured before and after PTX (days 1, 3, 7, and 10) by means of sandwich enzyme-linked immunosorbent assay. RESULTS: Preoperative FGF-23 levels correlated positively with phosphorus (P < 0.05), calcium-phosphorus product (Ca x P; P < 0.0005), and PTH values (P < 0.05). Serum FGF-23 levels decreased time dependently after PTX (P < 0.0005). Both serum phosphorus and Ca x P values decreased similarly after PTX ( P = 0.0001). Furthermore, FGF-23 levels days 1 and 3 correlated linearly with serum phosphorus (P < 0.05; P < 0.005, respectively) and Ca x P values (P < 0.01; P < 0.0001, respectively). CONCLUSION: FGF-23 levels correlate positively with serum phosphorus, Ca x P, and PTH values in patients with advanced secondary hyperparathyroidism. Complete ablation of progressive parathyroid glands reduces circulating FGF-23 levels, simultaneously decreasing serum phosphorus and Ca x P values. These findings suggest that hyperplastic parathyroid glands, together with hyperphosphatemia, affect abnormal FGF-23 metabolism in patients with stage 5 CKD with advanced secondary hyperparathyroidism.

[Role of vitamin D in the pathogenesis of renal osteodystrophy].

Renal osteodystrophy was occurred in patients with chronic renal failure and the biopsied patients had various forms of bone disease. Active vitamin D has an important role of calcium regulation and bone metabolism. In patients with end-stage renal disease, decreased levels of active vitamin D, reduced number of vitamin D receptors and calcium sensing receptors in parathyroid gland pay a major role in the development of hyperparathyroidism. It was invited osteitis fibrosa, high bone turnover. The parathyroid function is suppressed by active vitamin D, it was considered that lower parathyroid hormone levels was one of the cause of low bone turnover, adynamic bone disease.

[Mechanism of secondary hyperparathyroidism].

Renal osteodystrophy is an important concomitant disease in chronic renal failure. Secondary hyperparathyroidism cause high turnover bone. Hypocalcemia and phosphate retention stimulate the parathyroid and to proliferation of the parathyroid cells. In these days vitamin D deficiency, resistance to vitamin D, abnormality of sensitivity to calcium, direct effect of phosphorus , more severe form of parathyroid hyperplasia, abnormality of gene and increased skeletal resistance to PTH are pointed as cause of parathyroid hyperfunction.

[Calcium and vitamin D metabolism in the kidney-parathyroid system].

Calcium level is maintained by parathyroid hormone, 1alpha, 25 (OH)(2)D(3) and calcitonin in cooperation with bone, kidney and intestine. In the kidney activation of vitamin D and transcellular calcium transport in distal tubule regulate calcium concentlation. In the parathyroid glands calcium-sensing receptor sense extracellular calcium and secretes parathyroid hormone. It is received negative feedback from 1alpha, 25 (OH)(2)D(3) and phosphate.